An implantable medical device (IMD) is a device placed inside a body to monitor certain physiological signals and provide therapy to an organ or tissue in response to the physiological signals. The IMD may be, for example, but not by way of limitation, a pacemaker. For convenience, all types of implantable medical devices will be referred to herein as IMDs, it being understood that the term, unless otherwise indicated, is inclusive of an implantable device capable of administering any of a number of therapies to the heart or other organs or other tissue of the patient. For convenience the present invention will be described in terms of a cardiac pacemaker lead, it being understood that the invention also may have applicability to other types of leads, which deliver therapy to alternates sites and according to other modalities known to those skilled in the art.
Typically, leads are coupled or attached to heart tissue using an a helix-coil that is wound or “screwed” into the tissue or using tined protrusions which catch in tissue in proximity to an implant site. In some cases, helix-coil electrodes and tines may not necessarily result in a secure attachment, for example if the tissue does not facilitate such attachment or if a lead is of such a small size to prevent secure attachment. Accordingly, it is desirable to provide improved means for securely attaching a medical lead to tissue of a human or animal.